The present invention relates to a water-proof connector or more in particular to a water-proof connector using a water-proof seal ring in the coupling of a female connector housing and a male connector housing, or especially an engaging construction of a water-proof seal ring ("O" ring).
Four types of construction of water-proof seal ring engaging constructions shown in FIGS. 1A to 1D are well known for conventional water-proof connectors. In FIG. 1A, a seal ring 3 is fitted on the misalignment 1b formed at the forward end 1a of a female connector housing 1, a holder 4 for preventing separation of the seal ring 3 is mounted at the forward end 1a of the female connector housing, and the female connector housing 1 is coupled with a male connector housing 2. Reference numeral 7 designates a male connector. A female connector is not shown in the drawing.
In FIG. 1B, on the other hand, an annular slot for the seal ring 3 is formed near the forward end 1a of a female connector housing 1, and the seal ring 3 is fitted in the annular slot 5.
The construction of the water-proof connector shown in FIG. 1C is such that a seal ring 3 is fitted in a recess 6 at the last half portion 2b of a male connector housing 2, the first half portion 2a of the male connector housing 2 doubling as a member for preventing separation of the seal ring 3 is brought into contact with the seal ring 3, and the outer peripheries of the first and second half portions are welded to each other thereby to fixedly engage the seal ring 3.
The water-proof connector of FIG. 1D is so constructed that an annular engaging protrusion 8 is formed in the recess 6 of the male housing 2, and a seal ring 3 is fixedly fitted between the bottom and the engaging protrusion 8 of the recess 6.
The above-described conventional engaging constructions have the disadvantages mentioned below respectively.
The construction of FIG. 1A requires a considerable number of parts, the others resulting in a high cost and involves more steps due to the requirement of the holder to be fixed by welding or like means. In the construction of FIG. 1B, the annular slot 5 is required to be molded integrally with the female housing 1 by use of a couple of vertically-split dies, which unavoidably causes a burr along the part line separating the upper and lower dies, thus deteriorating the sealing performance. The water-proof connector of FIG. 1C is bulkier than those of FIGS. 1A or 1B, and also, because of the requirement of welding equipment such as ultrasonic welder, is impractically high in cost. Lastly, in the construction of FIG. 1D, the height of the engaging protrusion 8 is limited to 0.3 to 0.5 mm for processing reasons, so that the seal ring 3 is liable to come off during transportation on the one hand and upon mounting or demounting of the female connector housing 1, the seal ring 3 is sometimes reversed and peeled or separated off by the fitting or separation resistance respectively. Further, the seal rings 3 of the constructions of FIGS. 1A and 1B are fitted exposed on the outer periphery, and therefore is often damaged in contact with other members. In the constructions of FIGS. 1C and 1D, by contrast, in spite of the advantage of the seal ring 3 being built in and protected from damage, the seal ring 3 cannot be visually identified from outside.